The importance of the solid–electrolyte interphase (SEI) for reversible operation of Li-ion batteries has been well established, but the understanding of its chemistry remains incomplete. The current consensus on the identity of the major organic SEI component is that it consists of lithium ethylene di-carbonate (LEDC), which is thought to have high Li-ion conductivity, but low electronic conductivity (to protect the Li/C electrode). Here, we report on the synthesis and structural and spectroscopic characterizations of authentic LEDC and lithium ethylene mono-carbonate (LEMC). Direct comparisons of the SEI grown on graphite anodes suggest that LEMC, instead of LEDC, is likely to be the major SEI component. Single-crystal X-ray diffraction studies on LEMC and lithium methyl carbonate (LMC) reveal unusual layered structures and Li+ coordination environments. LEMC has Li+ conductivities of >1 × 10−6 S cm−1, while LEDC is almost an ionic insulator. The complex interconversions and equilibria of LMC, LEMC and LEDC in dimethyl sulfoxide solutions are also investigated.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $13.33 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Crystallographic data for the structures reported in this work have been deposited at the Cambridge Crystallographic Data Centre (CCDC) under deposition nos. CCDC 1847784 (LEMC) and CCDC 1847785 (LMC). Copies of the data can be obtained free of charge via www.ccdc.cam.ac.uk/structures. Data supporting the findings of this study are available within this paper and its Supplementary Information, and are available from the corresponding author upon reasonable request. The MAS NMR experimental and GIPAW calculated data for this study are provided as a supporting dataset from WRAP, the Warwick Research Archive Portal at http://wrap.warwick.ac.uk/120226.
Winter, M., Barnett, B. & Xu, K. Before Li ion batteries. Chem. Rev. 118, 11433–11456 (2018).
Yazami, R. & Touzain, P. A reversible graphite-lithium negative electrode for electrochemical generators. J. Power Sources 9, 365–371 (1983).
Persson, K. et al. Lithium diffusion in graphitic carbon. J. Phys. Chem. Lett. 1, 1176–1180 (2010).
Persson, K., Hinuma, Y., Meng, Y. S., Van der Ven, A. & Ceder, G. Thermodynamic and kinetic properties of the Li-graphite system from first-principles calculations. Phys. Rev. B 82, 125416 (2010).
Goodenough, J. B. & Kim, Y. Challenges for rechargeable Li batteries. Chem. Mater. 22, 587–603 (2010).
Xu, K. Electrolytes and interphases in Li-ion batteries and beyond. Chem. Rev. 114, 11503–11618 (2014).
Verma, P., Maire, P. & Novák, P. A review of the features and analyses of the solid electrolyte interphase in Li-ion batteries. Electrochim. Acta 55, 6332–6341 (2010).
Dahn, J. R., Zheng, T., Liu, Y. & Xue, J. Mechanisms for lithium insertion in carbonaceous materials. Science 270, 590 (1995).
Levi, M. D. & Aurbach, D. The mechanism of lithium intercalation in graphite film electrodes in aprotic media. Part 1. High resolution slow scan rate cyclic voltammetric studies and modeling. J. Electroanal. Chem. 421, 79–88 (1997).
Aurbach, D., Markovsky, B., Shechter, A., Ein‐Eli, Y. & Cohen, H. A comparative study of synthetic graphite and Li electrodes in electrolyte solutions based on ethylene carbonate‐dimethyl carbonate mixtures. J. Electrochem. Soc. 143, 3809–3820 (1996).
Zhang, X., Kostecki, R., Richardson, T. J., Pugh, J. K. & Ross, P. N. Electrochemical and infrared studies of the reduction of organic carbonates. J. Electrochem. Soc. 148, A1341–A1345 (2001).
Peled, E. The electrochemical behavior of alkali and alkaline earth metals in nonaqueous battery systems—the solid electrolyte interphase model. J. Electrochem. Soc. 126, 2047–2051 (1979).
Fong, R., Von Sacken, U. & Dahn, J. R. Studies of lithium intercalation into carbons using nonaqueous electrochemical cells. J. Electrochem. Soc. 137, 2009–2013 (1990).
Nie, M. et al. Lithium ion battery graphite solid electrolyte interphase revealed by microscopy and spectroscopy. J. Phys. Chem. C 117, 1257–1267 (2013).
Aurbach, D. et al. The study of electrolyte solutions based on ethylene and diethyl carbonates for rechargeable Li batteries II. Graphite electrodes. J. Electrochem. Soc. 142, 2882–2890 (1995).
Winter, M., Novák, P. & Monnier, A. Graphites for lithium‐ion cells: the correlation of the first‐cycle charge loss with the Brunauer–Emmett–Teller surface area. J. Electrochem. Soc. 145, 428–436 (1998).
Winter, M. The solid electrolyte interphase—the most important and the least understood solid electrolyte in rechargeable Li batteries. Z. Phys. Chem. 223, 1395–1406 (2009).
Edström, K., Herstedt, M. & Abraham, D. P. A new look at the solid electrolyte interphase on graphite anodes in Li-ion batteries. J. Power Sources 153, 380–384 (2006).
Yoshida, T. et al. Degradation mechanism and life prediction of lithium-ion batteries. J. Electrochem. Soc. 153, A576–A582 (2006).
Malmgren, S. et al. Comparing anode and cathode electrode/electrolyte interface composition and morphology using soft and hard X-ray photoelectron spectroscopy. Electrochim. Acta 97, 23–32 (2013).
Lu, P., Li, C., Schneider, E. W. & Harris, S. J. Chemistry, impedance and morphology evolution in solid electrolyte interphase films during formation in lithium ion batteries. J. Phys. Chem. C 118, 896–903 (2014).
Zhuo, Z. et al. Breathing and oscillating growth of solid–electrolyte-interphase upon electrochemical cycling. Chem. Commun. 54, 814–817 (2018).
Shi, S. et al. Direct calculation of Li-ion transport in the solid electrolyte interphase. J. Am. Chem. Soc. 134, 15476–15487 (2012).
Zhuang, G. V. & Ross, P. N. Analysis of the chemical composition of the passive film on Li-ion battery anodes using attentuated total reflection infrared spectroscopy. Electrochem. Solid State Lett. 6, A136–A139 (2003).
Meyer, B. M., Leifer, N., Sakamoto, S., Greenbaum, S. G. & Grey, C. P. High field multinuclear NMR investigation of the SEI layer in lithium rechargeable batteries. Electrochem. Solid State Lett. 8, A145–A148 (2005).
Aurbach, D. & Gofer, Y. The behavior of lithium electrodes in mixtures of alkyl carbonates and ethers. J. Electrochem. Soc. 138, 3529–3536 (1991).
Augustsson, A. et al. Solid electrolyte interphase on graphite Li-ion battery anodes studied by soft X-ray spectroscopy. Phys. Chem. Chem. Phys. 6, 4185–4189 (2004).
Zhuang, G. V., Xu, K., Yang, H., Jow, T. R. & Ross, P. N. Lithium ethylene dicarbonate identified as the primary product of chemical and electrochemical reduction of EC in 1.2 M LiPF6/EC: EMC electrolyte. J. Phys. Chem. B 109, 17567–17573 (2005).
Zhuang, G. V., Yang, H., Blizanac, B. & Ross, P. N. A study of electrochemical reduction of ethylene and propylene carbonate electrolytes on graphite using ATR-FTIR spectroscopy. Electrochem. Solid State Lett. 8, A441–A445 (2005).
Shkrob, I. A., Zhu, Y., Marin, T. W. & Abraham, D. Reduction of carbonate electrolytes and the formation of solid-electrolyte interface (SEI) in lithium-ion batteries. 2. Radiolytically induced polymerization of ethylene carbonate. J. Phys. Chem. C 117, 19270–19279 (2013).
Tsubouchi, S. et al. Spectroscopic characterization of surface films formed on edge plane graphite in ethylene carbonate-based electrolytes containing film-forming additives. J. Electrochem. Soc. 159, A1786–A1790 (2012).
Ota, H., Sakata, Y., Wang, X., Sasahara, J. & Yasukawa, E. Characterization of lithium electrode in lithium imides/ethylene carbonate and cyclic ether electrolytes II. Surface chemistry. J. Electrochem. Soc. 151, A437–A446 (2004).
Kang, S.-H., Abraham, D., Xiao, A. & Lucht, B. Investigating the solid electrolyte interphase using binder-free graphite electrodes. J. Power Sources 175, 526–532 (2008).
Liu, P. & Wu, H. Construction and destruction of passivating layer on LixC6 in organic electrolytes: an impedance study. J. Power Sources 56, 81–85 (1995).
Xu, K. & von Wald Cresce, A. Li+-solvation/desolvation dictates interphasial processes on graphitic anode in Li ion cells. J. Mater. Res. 27, 2327–2341 (2012).
von Wald Cresce, A., Borodin, O. & Xu, K. Correlating Li+ solvation sheath structure with interphasial chemistry on graphite. J. Phys. Chem. C 116, 26111–26117 (2012).
Aurbach, D., Daroux, M., Faguy, P. & Yeager, E. Identification of surface films formed on lithium in propylene carbonate solutions. J. Electrochem. Soc. 134, 1611–1620 (1987).
Shi, F. et al. A catalytic path for electrolyte reduction in lithium-ion cells revealed by in situ attenuated total reflection–Fourier transform infrared spectroscopy. J. Am. Chem. Soc. 137, 3181–3184 (2015).
Gireaud, L., Grugeon, S., Laruelle, S., Pilard, S. & Tarascon, J.-M. Identification of Li battery electrolyte degradation products through direct synthesis and characterization of alkyl carbonate salts. J. Electrochem. Soc. 152, A850–A857 (2005).
Michan, A. L., Leskes, M. & Grey, C. P. Voltage dependent solid electrolyte interphase formation in silicon electrodes: monitoring the formation of organic decomposition products. Chem. Mater. 28, 385–398 (2015).
Xu, K. et al. Syntheses and characterization of lithium alkyl mono-and dicarbonates as components of surface films in Li-ion batteries. J. Phys. Chem. B 110, 7708–7719 (2006).
Seo, D. M. et al. Reduction reactions of carbonate solvents for lithium ion batteries. ECS Electrochem. Lett. 3, A91–A93 (2014).
Kamaya, N. et al. A lithium superionic conductor. Nat. Mater. 10, 682 (2011).
Han, F., Gao, T., Zhu, Y., Gaskell, K. J. & Wang, C. A battery made from a single material. Adv. Mater. 27, 3473–3483 (2015).
Knauth, P. Inorganic solid Li ion conductors: an overview. Solid State Ion. 180, 911–916 (2009).
Gurusiddappa, J., Madhuri, W., Suvarna, R. P. & Dasan, K. P. Studies on the morphology and conductivity of PEO/LiClO4. Mater. Today Proc. 3, 1451–1459 (2016).
Schafzahl, L. et al. Long-chain Li and Na alkyl carbonates as solid electrolyte interphase components: structure, ion transport and mechanical properties. Chem. Mater. 30, 3338–3345 (2018).
Zhuang, G. V., Yang, H., Ross, P. N., Xu, K. & Jow, T. R. Lithium methyl carbonate as a reaction product of metallic lithium and dimethyl carbonate. Electrochem. Solid State Lett. 9, A64–A68 (2006).
Pickard, C. J. & Mauri, F. All-electron magnetic response with pseudopotentials: NMR chemical shifts. Phys. Rev. B 63, 245101 (2001).
Yates, J. R., Pickard, C. J. & Mauri, F. Calculation of NMR chemical shifts for extended systems using ultrasoft pseudopotentials. Phys. Rev. B 76, 024401 (2007).
Gachot, G. et al. Deciphering the multi-step degradation mechanisms of carbonate-based electrolyte in Li batteries. J. Power Sources 178, 409–421 (2008).
Xu, K. Whether EC and PC differ in interphasial chemistry on graphitic anode and how. J. Electrochem. Soc. 156, A751–A755 (2009).
The authors thank the DOE for funding this research through the EFRC (NEES-II) and Energy Hub (JCESR). B.W.E. thanks J. Davis for many helpful discussions. A.M. thanks the University of Warwick for a Chancellor’s International Scholarship. The UK 850 MHz solid-state NMR Facility used in this research is funded by EPSRC and BBSRC, as well as the University of Warwick, including via part funding through Birmingham Science City Advanced Materials Projects 1 and 2 supported by Advantage West Midlands (AWM) and the European Regional Development Fund (ERDF). O.B. acknowledges support via NASA agreement NND16AA29I.
The authors declare no competing interests.
Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Nature Chemistry (2019)